Re: [fuse-devel] [PATCH] FUSE/CUSE: implement direct mmap support

From: Tejun Heo
Date: Wed Feb 10 2010 - 18:41:58 EST


Hello,

On 02/11/2010 12:02 AM, Miklos Szeredi wrote:
>> Yeah, sure. FUSE server is free to give them separate regions. The
>> only restriction is the SHMLBA alignment which is pretty easy to
>> adhere to.
>
> What I really meant was: does it ever happen that mapping a *single
> open file* of a chardev twice will result in two different maps?
> Or will the maps be only different if it was a different open of the
> device?

I don't know if there is one but ->mmap() implementation is definitely
allowed to do that.

> If there's a pattern there, we might make the sharing/non-sharing
> automated, and greatly simplify the interface.

Isn't the interface pretty simple as it is? If we want to make it
easier for API users by imposing limits, I think the correct layer to
do that would be at the library level.

Thanks.

--
tejun
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